1. Field of the Invention
The present invention relates to a wide-band reproducing speaker which can reproduce a very high sound band up to 70 kHz, for example.
2. Description of the related Art
In general, a whole band speaker having a small aperture (diameter), for example, an aperture of 39 mm, is constructed in a manner that a voice coil bobbin is attached to an inner circumferential portion of a cone type diaphragm while a voice coil is wound around the voice coil bobbin, and the voice coil is inserted into a magnetic gap. However, in the above speaker, it is difficult to reproduce (radiation) a very high sound band, and further, a reproducing sound band by the speaker is up to 40 kHz to the utmost from the reason why a weight of the voice coil is heavy.
The present invention has been made in view of the above problem. It is, therefore, an object of the present invention to provide a cone type speaker which can reproduce a very high sound band up to 70 kHz, for example.
To achieve the above object, the present invention provides a speaker which is constructed in a manner that a voice coil bobbin is attached to an inner circumferential portion of a cone type diaphragm while a voice coil is wound around the voice coil bobbin, and the voice coil is inserted into a magnetic gap, characterized in that the voice coil bobbin is formed of a conductive material while the voice coil bobbin is provided with a gap extending a lengthwise direction so as to form one-turn voice coil, and the voice coil is fixed to the voice coil bobbin by a soft bonding agent while a very high frequency audio signal is supplied to one-turn voice coil comprising the voice coil bobbin.
According to the present invention, the voice coil bobbin comprises as one-turn voice coil while a very high frequency audio signal is supplied the voice coil, and the voice coil is fixed to the voice coil bobbin by a soft bonding agent. In a very high sound band, a bonding force by the soft bonding agent lowers, and then, the voice coil bobbin and the voice coil become a state of separating from each other. Therefore, the voice coil bobbin is operated as one-turn voice coil, and then, a diaphragm is vibrated by only very light voice coil bobbin, and thereby, the voice coil before separating from the voice coil bobbin has no mass. As a result, by a difference in mass, it is possible to a very high sound band up to 70 kHz, for example.